This invention relates to an improved connection between pressure containing components of a fluid or gas system device, and in particular to a crimp joint that joins and secures components to each other and that has increased strength compared to prior crimp joints. The crimp joint comprises a flange extending from a first component and a cavity of a second component that accepts and closely surrounds the flange. The flange is defined by a flange mating surface and an engaging surface that face in generally opposite directions and extend from the first component to an outer flange edge. The cavity of the second component is defined by a second mating surface that is configured to conform to the flange mating surface and a lip that extends from the second mating surface to closely surround the outer flange edge. The lip extends from the second mating surface a distance that is greater than the width of the flange between the flange mating surface and the engaging surface. The crimp joint is formed by first positioning the flange within the cavity with the flange mating surface adjacent to the second mating surface. The lip is deformed toward the flange to overlie and conform to the engaging surface capturing the flange between the second mating surface and the deformed lip overlying the flange. The engaging surface of the flange is configured to abut the lip to prevent deformation of the lip to an extent that would weaken the lip and is configured to deform and to deform and engage the lip to provide a crimped joint of increased strength compared to prior crimp joints.
Fluids and gas are distributed through systems of pipes or tubing that include pumps, valves, regulators, and other devices that control and direct movement of a fluid or gas through the system. In addition to performing their specific function within the distribution system, these devices must contain the fluid or gas within the device without leakage.
Devices used in fluid and gas distribution systems have varying degrees of mechanical complexity that depend on the system within which they are used and on their functions within the system. Most such components have internal components that cannot be reasonably assembled within the small space that they occupy in their assembled and functioning configuration. Manufacturing considerations require that the exterior of these devices be formed from separate, outer components that are joined to each other after the internal components are assembled and mounted to these outer components. The outer components of such devices generally form a barrier between the fluid or gas with in the system and the environment surrounding the system. The joints between outer components must be both strong and leak-proof.
One measure of the strength of the joint between outer components of a fluid or gas distribution system device is the amount of pressure within the device that can be contained without either leaking through the joint or failure of the joint. In addition to securing outer components to each other in a leak-proof manner, the joint between outer components may also be required to engage and support internal components of the device.
Different joints have been used to join outer components of fluid or gas distribution system devices depending on the requirements of the joint. Bolted joints are commonly used to provide a joint that has high strength and is leak-proof. Bolted joints are typically formed by two flanges, each joined component forming one of the flanges, that are configured to conform to each other along mating surfaces that are positioned adjacent to each other. Both flanges have holes extending from the mating surfaces that are aligned with a hole of the adjacent flange. One of several conventional threaded fastener configurations may be used to secure the flanges to each other. A bolt may extend through aligned holes of both flanges from a surface of one flange opposite the mating surface to position a bolt head abutting that opposite surface. The bolt may extend through the other flange to engage a nut that is threaded onto the bolt to abut a surface of the other flange opposite the mating surface. Alternatively, the hole of the second flange may be threaded to engage the bolt eliminating the need for a nut to engage the bolt. A threaded stud may be used in place of a bolt either to engage threads of one flange or to extend through both flanges and have nuts threaded onto the portions of the threaded stud that extend beyond the flange.
Bolted joints can provide a wide range of joint strengths depending on the size and separation of the bolts. A disadvantage of bolted joints is that they require several manufacturing operations, which can include machining the mating surfaces, drilling holes, and threading holes. Bolted joints also require bolts or threaded studs and nuts, and require assembly and tightening of the bolts to secure the components to each other. These operations are time consuming making bolted joints relatively expensive.
A less expensive joint that has been used to join components of fluid and gas distribution systems is a crimp joint. Crimp joints in the prior art have conventionally been formed by a uniform thickness flange extending generally perpendicularly from the outer surface of a first component and a lip of a second component that is deformed to overlie the flange and secure it against a mating surface of the second component. These prior art crimp joints are less expensive to manufacture and assemble than bolted joints. There are several disadvantages of prior art crimp joints that have limited their use.
One significant problem associated with such prior art crimp joints relates to the deformation of the lip that is required to capture the flange. Where the flange is perpendicular to the surrounding lip, the surrounding lip must be deformed so that a portion of the lip is perpendicular to its original configuration. This requires a large deformation of the surrounding lip and therefor requires that the lip be made of a material that will sustain such large deformation without cracking, becoming brittle, or otherwise failing or becoming susceptible to later failure. Materials that can be so deformed, such as steel, are relatively expensive and therefor increase the cost of the device.
Less expensive material has been used to form components of a fluid or gas system device that have a crimp joint where, rather than having a flange that is perpendicular to a surrounding lip, a flange is formed to have an upper surface opposite the flange mating surface that extends from an outer edge of the flange and away from the flange mating surface so that the flange upper surface forms an angle with the lip that is less than a perpendicular angle. The surrounding lip of the second component then is deformed over the edge of the flange to abut upper surface by an angle that is less than ninety degrees to form the crimp joint. Because less deformation of the lip is required to form the joint than perpendicular flanges, the material from which the surrounding lip is made need not be capable of sustaining high strain and therefor can be a less expensive material compared to material required for larger deformation. A recognized disadvantage of such joints is that they are less strong than a joint formed by deforming the surrounding lip to an angle of ninety degrees.
A need remains for a crimp joint that can be formed by components made of materials that cannot sustain high strain and that provides increased strength compared to prior crimp formed from components made of such materials.
The present invention overcomes problems and disadvantages of prior crimp joints used to join components of fluid or gas distribution system devices. The joint according to the present invention comprises a flange that extends from a first component to a flange edge and a second component that defines a cavity to accept the flange. The cavity is defined by a second mating surface and a surrounding lip that extends from the second mating surface and is configured to closely surround the flange edge. The flange includes a flange mating surface that conforms to the second mating surface, and an engaging surface adjacent to the flange edge that preferably extends at least partially along the surrounding wall to form an angle with the surrounding wall that is less than ninety degrees when the flange mating surface is adjacent to the second mating surface. The engaging surface includes a bead that is formed to extend outwardly from the engaging surface at a location that is sufficiently near the flange edge that the surrounding lip will overlie the bead when the lip is deformed to overlie the engaging surface.
The crimped joint is formed by placing the flange of the first component in the cavity of the second component with the flange mating surface adjacent to the second mating surface of the second component. The surrounding lip is closely adjacent to the flange edge and is deformed toward the engaging surface of the flange until it overlies the engaging surface and conforms to the surface including the bead.
Accordingly, an object of the present invention is to provide a crimp joint that is less costly than prior crimp joints that support significant loads.
Another object of the present invention is to provide a crimp joint that does not require components of the joint to be manufactured from materials that can sustain high strains.
Yet another object of the present invention is to provide a crimp joint that provides greater strength than prior crimp joints formed by component made of materials that will not sustain high strains.
These and other objects and advantages of the present invention will be understood from the following description and drawings of an embodiment of a crimp joint according to the present invention.